Yes.. Because the joists run lengthwise to the tank, I added 2 more joists as well as two 2X8 studded bearing walls directly under the centerline on the tank - Basically a 16" thick studded wall with a 2X8 bearing wall running the width of the tank forming a 'T' wall under the centerline of the tank. The other end closest to the window sits directly over the concrete foundation wall as my livingroom is cantalevered out 24"
Additional photos can be seen here;
http://reefcentral.com/gallery/showg...1&ppuser=35561